shunt diode safety barriers mtl 7700 series data sheet diode safety barriers mtl 7700 series ... ♦...

Shunt diode safety barriers MTL 7700 Series Data Sheet

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DIN rail mountingsafety barriers

MTL7700 SERIES

Since its introduction in 1984 the MTL700Series barrier has established itself as the worldwidestandard for safety barriers. Known for its qualityand reliability, the MTL700 Series is widely used inapplications all over the world.

The MTL7700 Series follows closely in thefootsteps of the MTL700 but as a DIN rail mountingbarrier providing quick and easy installation withoutthe need for special hardware.

Removable terminals are used for ease ofinstallation, maintenance and for providing a loopdisconnect by simply unplugging the terminals fromthe side of the module. Wire entry is also angled toassist wiring within limited space enclosures.

MTL7700 barriers clamp simply and securelyonto standard T-section DIN rail, simultaneouslymaking a reliable IS earth connection.

For applications where field power isrequired for switch inputs or 2-wire transmitters, theMTL7700 Series provides a bussed power feedfacility. When used in conjunction with the MTL7798power feed module the user has a fully protected,electronically fused supply to many barriers with noadditional wiring required.

MTL7700 active modules are protected with anelectronic fuse for the majority of applications. TheMTL7798 active fused, power feed module canprotect up to 40 other modules using the bussedpower facility and provides a clear indication of atrip condition via a red LED.

The MTL774X range of barriers offer a NAMURcompatible input and a choice of relay or solid stateoutput. The solid state outputs are floating soswitching to ground or from a power rail into aninput is also possible. The solid state interface alsoprovides a high frequency transfer for use in flow orrotation applications.

Dual channel relay or solid state modules offerthe highest packing density with only 6.3mm perchannel and when used in conjunction with thepower bus, offer users the minimum of wiring withthe maximum packing density and the lowest costper channel.

♦♦ Proximity detector inputs

♦♦ Electronic fusing

♦♦ Direct replacement for MTL700 Series barriers

♦♦ Compatible terminal numbering and safety descriptions

♦♦ Removable terminals

♦♦ Bussed power feed to other modules

♦♦ Relay and solid state switch modules

♦♦ Dual channel variants — 6.3mm per channel

EUROPE (EMEA) Tel: +44 (0)1582 723633 Fax: +44 (0)1582 422283AMERICAS Tel: +1 603 926 0090 Fax: +1 603 926 1899ASIA PACIFIC Tel: +65 487 7887 Fax: +65 487 7997E-mail: [email protected] Web site: www.mtl-inst.com

June 2004


June 2004

MTL V ΩΩ mA

7706+ 28 300 93 √√ Transmitters 35 507707+ 28 300 93 √√ Switches – 35 50

28 diode 35 507707P+ 28 164 171 √√ Transmitters, switches, 35 50

28 diode – controller outputs IIB 35 50

7710+ 10 50 200 √√ 6V dc & 4V ac systems 75 6.0 7.0 507715+ 15 100 150 √√ 12V systems 119 12.0 13.1 1007715P+ 15 50 291 √√ 12V dc systems 64 12.6 13.7 1007722+ 22 150 147 √√ 18V dc systems 174 19.6 20.2 507728+ 28 300 93 √√ Controller outputs, solenoids 333 25.9 26.5 507728- 28 300 93 √√ Transmitters 333 25.9 26.5 507728ac 28 300 93 √√ 333 25.0 25.9 507728P+ 28 234 119 √√ Controller outputs, solenoid valves 252 24.9 25.9 1007729P+ 28 164 170 √√ Controller outputs, solenoid valves IIB 184 24.9 25.9 100

Prox sw input,774X 10 — 19 solid state output — — 30/35 50

and line fault detect

7755ac 3 10 300 √√ 2 or 3- Wire RTDs 19.0 (1) 3.4 2503 10 300 √√ (floating bridge) 19.0 (1) 3.4 250

7756ac 3 10 300 √√ 3 - Wire RTDs 19.0 (0.7) 2.7 2503 10 300 √√ (grounded bridge) 19.0 (0.7) 2.7 2503 10 300 √√ 19.0 (0.7) 2.7 250

7758+/- 7.5 10 750 √√ √√ Gas detectors 17 6.0 7.3 2007.5 10 750 17 6.0 7.3 200

7761ac 9 90 100 √√ 107 6.0 7.0 1009 90 100 107 6.0 7.0 100

7761Pac 9 350 26 √√ Strain-gauge bridges 378 6.8 7.5 509 350 26 378 6.8 7.5 50

7764+/ac 12 1k 12 √√ √√ Strain-gauge bridges 1050 10.0 10.9 5012 1k 12 1050 10.0 10.6 50

7766ac 12 150 80 √√ 174 10.0 10.6 5012 150 80 174 10.0 10.6 50

7766Pac 12 75 157 √√ Strain-gauge bridges 92 9.6 10.5 10012 75 157 Strain-gauge bridges 92 9.6 10.5 100

7767+ 15 100 150 √√ 12V dc systems 119 12.0 13.1 10015 100 150 12V dc systems 119 12.0 13.1 100

7779+ 28 300 93 √√ Controller outputs requires channels 333 25.9 26.5 5028 300 93 Controller outputs separate in IIC 333 25.9 26.5 50

7796+ 26 300 87 √√ Vibration probes 333 23.9 24.5 5020 390 51 428 18.3 18.9 50

7796- 26 300 87 √√ Vibration probes 333 23.9 24.5 5020 390 51 428 18.3 18.9 50

7760ac 10 50 200 √√ Active dc & ac sensors 75 6.0 6.7 5010 50 200 Thermocouples 75 6.0 6.7 50

7765ac 15 100 150 √√ 124 12.0 12.5 5015 100 150 124 12.0 12.5 50

7778ac 28 600 47 √√ 651 24.0 25.4 5028 600 47 651 24.0 25.4 50

7789+ 28 300 93a √√ Switch inputs / 651 26.6 27.2 50Signal returns 651 26.6 27.2 50

28 diode — 0.9V+26Ω 26.6 27.2 5028 diode — 0.9V+26Ω 26.6 27.2 50

7787+/- 28 300 93 √√ √√ Transmitters 333 26.6 27.2 5028 diode — Controller outputs, switches 0.9V+26ΩΩ 26.6 27.2 50

7787P+ 28 234 119 √√ 253 26.4 27.2 8028 diode — 0.9V+21Ω 26.4 27.2 80

7788+ 28 300 93 √√ 333 25.9 26.5 5010 50 200 √√ 75 6.0 7.0 50

7788R+ 28 300 93 √√ Transmitters 333 25.9 26.5 5010 50 200 √√ 75 6.0 7.0 50

Vmax

V

SPECIFICATIONS‘Key’ barriers shown in blue

For notes 1 to 7 see 'Terminology' (later in this section)

ModelNo.

Safety description Polaritiesavailable

+ – ac

Basic circuit

Hazardous Safe

Fuserating

mA

Vwkg at 10(1)µA

V

Max. end-to-end

resistanceΩΩ

Application1 2 3 4 5 6

a Terminals 3 & 7 connected together*Diagrams show positive versions. All diodes reversed on negative versions. Additional diodes fitted on ac versions.

See 'HOW THEY WORK'and

'ACTIVE / ELECTRONICALLYPROTECTED BARRIERS'

See 'ACTIVE / ELECTRONICALLYPROTECTED BARRIERS'

See additionalspecification


June 2004

GENERAL SPECIFICATION

Ambient temperature and humidity limits–20 to +60°C continuous working–40 to +80°C storage5–95% RH

Leakage currentFor ‘basic’ barriers with a working voltage of 5V or more, theleakage current decreases by at least one decade per voltreduction in applied voltage below the working voltage, over twodecades. For the MTL7755ac/7756ac it decreases by at leastone decade for a 0.4V reduction in applied voltage.

TerminationsRemovable terminals accommodate conductors up to 2.5mm2

(13AWG). Hazardous-area terminals are identified by bluelabels. Removal force >15N

Colour coding of barrier labelGrey: non-polarisedRed: positive polarity (MTL7706 negative to transmitter )Black: negative polarityWhite: dummy barrier, MTL7799

Weight140g approx

Mounting and earthingBy 35mm Top Hat DIN rail

DIMENSIONS (mm)

KEY MTL7700 SERIES BARRIERS SUMMARISED

HOW THEY WORKAll MTL7700 Series barriers are based on the same simple principle.Each channel contains two stages of pulse-tested Zener or forward-connected diodes and an ‘infallible’ terminating resistor. In the eventof an electrical fault in the safe area, the diodes limit the voltage thatcan reach the hazardous area and the resistor limits the current. Afuse protects the diodes, and the two stages of voltage limitationensure continued safety if either stage should fail. No active output-current limiting circuits are employed. All models are certified ‘ia’ forall zones and ‘IIC’ for all explosive atmospheres (except MTL7707P+and MTL7729P+, 'ia' 'IIB').

TERMINOLOGY1. Safety descriptionThe safety description of a barrier, eg ‘10V 50Ω 200mA’, refers tothe maximum voltage of the terminating Zener or forward diode whilethe fuse is blowing, the minimum value of the terminating resistor, andthe corresponding maximum short-circuit current. It is an indication ofthe fault energy that can be developed in the hazardous area, andnot of the working voltage or end-to-end resistance.

2. PolarityBarriers may be polarised + or –, or non-polarised (‘ac’). Polarisedbarriers accept and/or deliver safe-area voltages of the specifiedpolarity only. Non-polarised barriers support voltages of eitherpolarity applied at either end.

3. End-to-end resistanceThe resistance between the two ends of a barrier channel at 20°C, ieof the resistors and the fuse. If diodes or transistors are present, theirvoltage drop (transistors ON) is quoted in addition.

4. Working voltage (Vwkg)The greatest steady voltage, of appropriate polarity, that can beapplied between the safe-area terminal of a ‘basic’ barrier channeland earth at 20°C for the specified leakage current, with thehazardous-area terminal open circuit.

5. Maximum voltage (Vmax)The greatest steady voltage, of appropriate polarity, that can beapplied continuously between the safe-area terminal of any barrierchannel and earth at 20°C without blowing the fuse. For ‘basic’barriers, it is specified with the hazardous-area terminal open circuit;if current is drawn in the hazardous area, the maximum voltage forthese barriers is reduced. The ‘ac’ channels of ‘basic’ barriers andmost channels of overvolt-protected barriers withstand voltages of theopposite polarity also – see circuit diagrams.

6. Fuse ratingThe greatest current that can be passed continuously (for 1000 hoursat 35°C) through the fuse.

7. Star connectionIn star-connected barriers, the two channels are interlocked such thatthe voltage between them cannot exceed the working voltage, Vwkg:this allows for higher cable capacitance or inductance.

8. Maximum safe-area voltage (Um)The maximum permissible safe-area voltage (Um) for MTL7700 Seriesbarriers is 250V ac/dc. APPLICATION KEY BARRIER

Resistance temperature detectorsThermocouples, ac sensors

Transmitters, 2-wire, 4/20mA

Controller outputs, one line earthedController outputs, neither line earthed

Switches

Solenoids, alarms, LEDs

7756ac7760ac

7706+7787+

7728+7787+

7787+7741/3

7728

TYPEAnalogueinput (low-level)

Analogueinput (high-level)

Analogueoutput

Digital (on/off)input

Digital (on/off)output

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June 2004

ACTIVE / ELECTRONICALLYPROTECTED BARRIERS

ACTIVE / ELECTRONICALLY PROTECTED BARRIERSThe following barriers have built-in overvolt protection, allowing theiruse with unregulated power supplies. In many applications, eg, sensorinputs or controller outputs, there is insufficient power available toblow the barrier fuse and this additional protection is not necessary.However, where the barrier is connected to a power supply, eg, forenergising transmitters, switches, solenoids or local alarms, overvoltprotection allows the barriers to be used with unregulated suppliesand also gives protection against faulty wiring during commissioning.

MTL7706+ for 'smart' 2-wire 4/20mA transmittersThe MTL7706+ is a 1-channel shunt-diode safety barrier, with built-inelectronic overvolt protection, for energising a 2-wire, 4/20mAtransmitter in a hazardous area. It is powered from a positive supplyof 20–35V dc and delivers a 4/20mA signal into an earthed load inthe safe area. It is proof against short circuits in the field and in thesafe area and is extremely accurate. The MTL7706+ will passincoming communication signals up to 10kHz from a ‘smart’transmitter, while in the outgoing direction it will pass signals of anyfrequency likely to be encountered.

Since the MTL7706+ has no return channel for energising the load,the entire output of the single ‘28V’ channel is available to power thetransmitter, providing high output capability. This channel is negativelypolarised, and the safe-area signal is in fact the very current thatreturns through it from the hazardous area, the novel circuit beingenergised by a built-in floating dc supply derived from the external dcsource of power.

To prevent any leakage through the zener diodes and maximise theoutput voltage available at 20mA, the floating supply is given a risingvoltage/current characteristic. A separate circuit limits the current toprotect the fuse in the event of a short circuit in the hazardous area.With a 20V supply, the barrier will deliver 16.2V minimum at 20mAfor the transmitter and lines and consumes typically 45mA at 24Voperation.

BASIC CIRCUIT

ADDITIONAL SPECIFICATION

Safety description28V 300Ω 93mA

Supply voltage20 to 35V dc w.r.t earth

Output current4 to 20 mA

Voltage available to transmitter and lines16.2V @ 20mA with 250Ω load (negative w.r.t. earth)11.0V @ 20mA with 500Ω load (negative w.r.t. earth)

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HazardousArea

SafeArea

Accuracy±2µA under all conditions

Safe-area load resistance0 to 500Ω

Supply current45mA typical at 20mA and 24V supply60mA maximum at 20mA and 20V supply

MTL7707+ for switch inputs and switched outputsThe MTL7707+ is a 2-channel shunt-diode safety barrier similar to theMTL7787+ but with built-in electronic overvolt protection. It isintended primarily for safeguarding a hazardous-area switchcontrolling a relay, opto-coupler or other safe-area load from anunregulated dc supply in the safe area.The outgoing channel accepts supply voltages up to +35V and isprotected against reverse voltages: the return channel is unaffected byvoltages up to +250V.In normal operation the protection circuit introduces only a smallvoltage drop and shunts less than 1mA to earth, so its overall effect isminimal. If the supply voltage exceeds about 27V, however, causingthe Zener diodes to conduct – or if the safe-area load has a very lowresistance – the supply current is limited automatically to 50mA,protecting the fuse and power supply and enabling the loop tocontinue working.

BASIC CIRCUIT


Safety description28V 300Ω 93mA, terminals 1 to 328V Diode, terminals 2 -4

Supply voltage10 to 35V dc with respect to earth

Output currentUp to 35mA available

Maximum voltage drop (at 20ºC, current not limited)

Iout x 345Ω + 0.3V, terminals 1 to 3Iout x 25Ω + 0.9V, terminals 4 to 2

Supply currentIout + 1.6mA, supply <26VLimited to 50mA, supply >28V or low load resistance

MTL7707P+ for switch inputs and switchedoutputs, 2W Transmitters (IIB gases)The MTL7707P+ is a two-channel shunt-diode safety barrier similar tothe MTL7787P+, but is designed for use with group IIB gases andfeatures built-in electronic overvolt protection allowing use withunregulated power supplies up to 35V dc. It is intended primarily asa low cost solution for driving IIB certified 2-wire 4/20mAtransmitters, but can also be used with controller outputs with currentmonitoring, solenoid valves and switches. To protect the fuse andenable the loop to continue working, the supply current is limitedautomatically at 50mA should the output be short-circuited or excessvoltage applied.

HazardousArea

SafeArea

1

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June 2004

MTL7742 proximity sensor or switch inputwith solid state outputThe MTL7742 is a single channel switch/prox input barrier with anopen collector solid state interface to the safe area equipment. Thesolid state switch is especially useful for high frequency switchingapparatus including pulse and rotational sensors. The power busterminal can be used to connect power to the module and the inputpower supply range makes the module suitable for use withunregulated supplies

BASIC CIRCUIT

ADDITIONAL SPECIFICATIONSafety description

10V 19mASupply voltage

20 to 35V dc with respect to earthInput characteristics

Output energised if input >2.1mA(<2kΩ)Output de-energised if input <1.2mA(>10kΩ)

Output characteristicsOperating frequency dc to 2.5kHzMax off-state voltage 35VMax off-state leakage 10µAMax on-state voltage drop <1.41V @ 50mA

<1.22V @ 2mAtypically <1V

Max on-state current 50mASupply current

20mA maximum @ 24V

MTL7743 2 channel proximity sensor or switchinput and relay outputsThe MTL7743 is a dual channel switch/prox sensor input barrier witha relay interface. This module is ideal for applications where highchannel packing densities are required for digital inputs. Power isconnected using the power bus terminal.BASIC CIRCUIT


10V 19mA10V 19mA

Supply voltage22.9 to 30V dc with respect to earth

Input characteristicsRelay energised if input >2.1mA(<2kΩ)Relay de-energised if input <1.2mA(>10kΩ)

Relay Contacts*125V ac 0.5A. Resistive30V dc, 1A. Resistive

Supply current45mA maximum @ 24V

Response time <10ms

BASIC CIRCUIT


Safety description28V 164Ω 171mA, terminals 1 to 328V Diode, terminals 4 to 2

Supply voltage 10 to 35V dc with respect to earth

Output currentUp to 35mA available

Maximum voltage drop(at 20ºC, current not limited)

Iout x 218Ω + 0.3V, terminals 1 to 3Iout x 20.1Ω + 0.9V, terminals 4 to 2

Supply currentIout + 1.6mA, supply <26VLimited to 50mA, supply >28V or low load resistance

MTL7741 proximity sensor or switch input andrelay outputThe MTL7741 is a single channel switch/prox input barrier withchangeover relay contacts acting as the safe area interface. Relaycontacts provide a universal interface capable of switching a widerange of signals including ac, low level and high level voltages.Phase reversal is achieved by connecting the normally open ornormally closed contacts as required. The power bus terminal may beused to connect the module to a power source.BASIC CIRCUIT



22.9 to 30V dc with respect to earthInput characteristics

Relay energised if input >2.1mA(<2kΩ)Relay de-energised if input <1.2mA(>10kΩ)

Relay Contacts*125V ac 0.5A. Resistive30V dc, 1A. Resistive


Response time <10ms

HazardousArea

SafeArea

HazardousArea

SafeArea

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* There are limitations for use above 50V. Please refer to theInstruction Manual INM7700.

HazardousArea

SafeArea

HazardousArea

SafeArea


June 2004

MTL7744 2 channel proximity sensor or switchinputs with solid state outputsA dual channel version of the MTL7742. This module provides twosolid state interfaces for prox/switch inputs. Power is connected viathe power bus.

BASIC CIRCUIT


10V 19mA10V 19mA

Supply voltage20 to 35V dc with respect to earth

Input characteristicsOutput energised if input >2.1mA(<2kΩ)Output de-energised if input <1.2mA(>10kΩ)

Output characteristicsOperating frequency dc to 2.5kHzMax off-state voltage 35VMax off-state leakage 10µAMax on-state voltage drop 1.41V @ 50mA

1.22V @ 2mAtypically <1V

Max on-state current 50mASupply current

29mA maximum @ 24V

MTL7745 proximity sensor or switch inputwith relay output and line fault detectThe MTL7745 is a single channel switch/prox input barrier providingline fault detection. Proximity detectors or switches fitted with end-of-line resistors may be connected. Short circuit or open ciruit conditionsin the field wiring will generate an alarm condition. The LFD relaycontacts close when a fault is detected allowing the contacts to beconnected in parallel to provide a common alarm. The power busterminal can be used to connect power to this module.

BASIC CIRCUIT



22.9 to 30V dc with respect to earthInput characteristics

Output energised if input >2.1mA(<2kΩ)Output de-energised if input <1.2mA(>10kΩ)

LFD relay + Red LEDEnergised if input <50µA or <100Ω

Relay contacts*125V ac 0.5A. Resistive30V dc, 1A. Resistive


Response time <10ms

MTL7798 Power feed and protection moduleThe MTL7798 power feed module incorporates both voltage andcurrent sense mechanisms to protect barrier circuits by activating asolid state trip mechanism when fault or overload conditions occur inthe power source circuit. Resetting the module after tripping isachieved by interupting the supply to the unit. A red LED indicates acircuit trip condition and a green LED the availability of power at theoutputs. Bussed power for other modules is sourced from the top ofthe unit using the Bus Power Link BPL7700 or via terminals 1 and 2.

BASIC CIRCUIT

ADDITIONAL SPECIFICATIONInput voltage range (terminals 5&6)

20 to 26.8VMaximum input voltage capability

45VPower source requirements

>1.8ATrip mechanism

Minimum trip 26.8V @ 20°C (+18mV/°C)Output current range

0 to 800mAMaximum voltage drop

20mV @ 0mA, 1.0V @ 800mA load

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* There are limitations for use above 50V. Please refer to theInstruction Manual INM7700.

HazardousArea

SafeArea

HazardousArea

SafeArea

HazardousArea

SafeArea


June 2004

MTL7700 Series barriers protect devices located in all normallyoccurring explosive atmospheres, including air/flammable gasmixtures, dusts and fibres. Applications covered include theprotection of installations incorporating uncertified devices (‘simpleapparatus’) such as thermocouples, switches and resistive sensors, orseparately certified ‘energy storing’ (or ‘voltage producing’)apparatus including ac sensors, transmitters and current-to-pneumatic(I/P) converters. Recommended choices for specific applications arediscussed briefly in the following pages.

MTL7700 SERIESBARRIER APPLICATIONS

ANALOGUE INPUTS (HIGH LEVEL)

2-wire transmitters, 4/20mA, conventional and smartThe recommended barrier for use with 'conventional' and 'smart'4/20mA transmitters (fed by a 26V regulated supply) is theMTL7787+. This provides up to 12.9V (14.6V for MTL7787P+) atVwkg and 20mA for a transmitter and its lines as well as 5V for thetypical 250Ω load. This application and this barrier is suitable for usewith the optional power bus facility.

The MTL7706+ is recommended for applications where anunregulated supply of up to 35V is used. It provides 16.0V forconventional and Smart transmitters at 20mA, as well as 5V for atypical 250Ω load. With the MTL7706+ terminal 3 is negative withrespect to earth, so the connections to terminals 3 and 4 should bereversed.

3

4

1

2MTL7760acMTL7765MTL7778

RecorderControllerData loggerComputer

Compensating cable

3

4

1

2MTL7760ac Earth freesignal

PhotocellMicrophoneTurbineFlowmeter

+6.0V3

4

1

2MTL7760acVout0V

3

4

1

2MTL7788R+

250Ω1-5V

Power +26V

Power Bus

3

4

1

2MTL7796-Power -24V

Vout

0V

Probedriver

Transducer

Monitor

3

4

1

2MTL7706+MTL7787+MTL7787P+ 250Ω4 -20mA

Power +26V

Signal

Power Bus

1-5V

ANALOGUE INPUTS (LOW-LEVEL)

Thermocouples and mV sourcesThe recommended barrier for thermocouples and mV sources is theMTL7760ac. This 2-channel non-polarised barrier retains the ‘earth-free’ nature of the signal and, providing the receiver’s input ‘floats’,rejects common-mode ac and dc interference up to at least 7V and isunaffected by earth faults on the primary element.

HazardousArea

SafeArea

Vibration probesThe 3-wire transmitters used with vibration monitoring equipment areinvariably supplied by a –24V dc power supply – hence therecommended barrier choice is the negatively-polarised MTL7796–.

Slidewire displacement transducersThe simplest choice is the MTL7760ac. This barrier supplies powerand brings back a unipolar signal.

ac sensors, photocells, microphones and turbine flowmetersThe MTL7760ac is the recommended choice for these devices. Whilemany of these are designated ‘simple apparatus’ and thus do notneed certification, note that some ac sensors may be subject to asignificant level of inductance and will therefore need to be designedand certified for hazardous-area locations.


June 2004

RTDsFor 3-wire RTDs, a single MTL7755ac barrier is the most economicalchoice. This is suitable for use with a floating bridge – the two leadsfrom the bridge arms are protected by the barrier with the third(supply) lead being earthed through the barrier. The barrier has a lowend-to-end resistance of only 19Ω/channel to minimise span changesand its channels track within 0.15Ω (between –20 to +60°C) tominimise zero shift with temperature.

STRAIN-GAUGE BRIDGES

Single strain-gauge bridgesThis shows an arrangement using two or three barriers, which is safein IIC gases. With the MTL7761ac, the circuit is powered from a 14V,230Ω source; if the bridge resistance is 230Ω, then the bridgevoltage is 7V. If the bridge resistance is 350Ω, then the bridgevoltage is 8.4V.An MTL7764ac can be used to sense the bridge supply voltage.An MTL7761ac is used here for the mV output.An MTL7766Pac provides 12.3V for a 350Ω bridge with a 20Vsupply. MTL7761Pac's can be used for the sense and pick-off circuits.

HazardousArea

SafeArea

3

4

1

2MTL7756ac

Receiver

7 5

3

4

1

2MTL7755ac

Receiver

3

4

1

2

Receiver

3

4

1

2MTL7755acMTL7761ac

MTL7755acMTL7761ac

4-wire constant-current circuits do not need matched barrierresistances and can be protected by two MTL7761ac barriers. If theincrease in loop resistance is too great, use two MTL7755ac barriersinstead.

If the bridge circuit is already earthed, the third barrier channelprovided by an MTL7756ac is needed. For extreme accuracy, 3channels and an earth-free bridge can be used, a configuration thatcancels out the small errors due to barrier leakage.Channels 1 and 2 (those between terminals 1 & 2, and 2 & 4respectively) track to within 0.15Ω between –20 and 60°C.

3

4

1

2

+7V3

4

1

2MTL7761ac

MTL7764ac

3

4

1

2MTL7761ac

--7V

0V

Output (mV)

Sense+

—


June 2004

STRAIN-GAUGE BRIDGES (cont)

Double strain-gauge bridgesQuite frequently there is a demand to monitor two load cells, and apossible circuit, safe in IIC, is shown.Here, the lower voltage drop of the MTL7766Pac is an advantage.The MTL7766Pac supplies power to the bridge(s) whilst twoMTL7761Pac barriers interface with the sense and pick-off circuits.Using 350Ω bridge systems, the following voltages are availablefrom an MTL7766Pac with a ±10V supply:

1 bridge: 13.11V2 bridges: 9.75V

ANALOGUE OUTPUTS

Controller outputs (I/P converters)The single-channel MTL7728+ with a voltage drop of 6.66V at 20mAis the recommended choice for most controller outputs. Higher-powerversions are available: the MTL7728P+ (5.1V drop) is suitable for IICapplications; the MTL7729P+ (3.68V drop) for IIB applications.

HazardousArea

SafeArea

3

4

1

2

+10V3

4

1

2MTL7766Pac

MTL7761Pac

3

4

1

2MTL7761Pac

--10V

0V

Sense+

—

Output (mV)

3

4

1

2MTL7728+2

.2

3

4

1

2MTL7787+MTL7787P+

2

.2

3

4

1

2MTL7787+MTL7787P+

2

9

.2

The MTL7787+ and MTL7787P+ are also suitable for controllerscontaining a resistor which enables the return current to be monitoredfor high-integrity operation.

For controllers with an output circuit separated from the 0V rail by thecontrol transistor, the 2-channel MTL7787+ is the preferred choice asthe return channel can handle up to 26.6V allowing the control signalto be turned off completely. The voltage drop is 8.1V at 20mA. Ahigher-power version of the latter, the MTL7787P+, is also available.The return channel of these barriers handle up to 26.4V and themaximum voltage drop is only 6.38V


June 2004

DIGITAL (ON/OFF) INPUTS

SwitchesThe normal choice is the MTL7787+/7787P+ with a regulatedsupply. The MTL774X modules are recommended for applicationswhere an unregulated supply of up to 30V for relay output modules,or 35V for solid state output modules, is used.

The MTL7789+ offers a dual channel passive barrier for switch inputswhere the input current for each channel is <10mA.

DIGITAL (ON/OFF) OUTPUTS

Alarms, LEDs, solenoids valves, etcFor these applications, the MTL7728+ is recommended. Higher-powered versions are available: the MTL7728P+ is suitable for IICapplications; the MTL7729P+ for IIB applications.

If the control switch is to earth, then the 2-channel MTL7787+ barriershould be used, or, alternatively, the MTL7787P+ higher-powerversion. If the supply is poorly regulated use the MTL7707+.

The MTL7707+ is recommended for applications where anunregulated supply of up to 35V is used.

HazardousArea

SafeArea

3

4

1

2MTL7787+MTL7787P+

Power +26.6V

Signal

Power Bus

34

1

2

MTL7789+78

56

Power +26.6V

Power +26.6VLogic signal

Logic signal

Power Bus

34

12MTL7743

MTL774478

56

3'!'

3'!'

-

34

1

2MTL7745 5

6

620Ω

10kΩ

+22.9 - 30V

LFDCOMCH 1

Power Bus

34

12

MTL7742 56 3'!'

3'!'

-%

.22

2

34

12

MTL7741 56

78 ;,

",9

-%

22;"

+26V3

4

1

2

0V

3678 MTL7707+

MTL7787+MTL7787P+

Switches / Proximity detectorsMTL’s range of new switch/prox input barriers provide the user witha choice of relay and solid state outputs in single and dual channelversions.

The MTL7741 is single channel with a changeover relay output.

The MTL7743 and MTL7744 are dual channel versions affordingvery high packing densities. Power must be provided to thesemodules using the power bus facility.

The MTL7745 is a single channel proximity input (or switch input if‘end of lines’ resistors are fitted) with relay contacts providing switchand line fault status. The LFD relay contacts close when a fault isdetected.

The MTL7742 has a single channel solid state switch that can beconfigured to switch from a power rail or down to ground. This is alsoideal for high switching frequency applications.

+24.9V3

4

1

2MTL7707+MTL7728+MTL7728P+MTL7729P+

0V

3678


June 2004

SPARE CABLE CORES AND SCREENS

The MTL7799 dummy barrier is used primarily for securing andearthing unused cables and screen connections. Hazardous areaterminals 3 and 4 are internally connected to the DIN-railmounting/earth connection. It also provides a power bus connectionfor direct connection of power for modules such as the MTL7743 andMTL7744 where no power supply screw terminal is provided.

POSITIVE DC SYSTEMS

Low-level to 12V dc systemsThe two channels of the MTL7764+ and MTL7767+ can be combinedsafely in IIC.

The MTL7764+ can be used for low-level logic return signals whilstthe MTL7767+ is used for 6V dc and 12V dc systems.

18V dc systemsThe single-channel MTL7722+ is recommended for 18V dc systems.

AC AND DC SYSTEMS

High-level ac and dc systemsThe versatile star-connected MTL7765ac and MTL7778ac allow Vwkgto be developed from each channel to ground but only allow Vwkg tobe developed between channels. This provides some common-modevoltage capability and can allow higher cable parameters to be used.

NEGATIVE AND FLOATING POWER SUPPLIES

Digital (on/off) outputsThe MTL7728– is used with a negative power supply and positiveearth. Typically used for digital inputs or outputs, as shown.

The MTL7728-- can also be used with floating power supplies, fortransmitters.

HazardousArea

SafeArea

3

4

1

2

0V

MTL7764+MTL7767+

!) +10V/+12V

+10V/+12V

3

4

1

20VMTL7722+

!)

+19.6V

3

4

1

2MTL7765acMTL7778ac!!

)12V/24V?0V

+26V

3

4

1

23678 MTL7728—

.

3

4

MTL7799

@ !!!

1

-%


June 2004

POWER BUS APPLICATIONS

The PB7700 power bus is invaluable for saving installation time andwiring when connecting a 24V dc power source to a number ofbarriers.

Typical applications include hazardous-area switches, 4/20mAtransmitters and proximity detectors. The diagram illustrates theconfiguration for 4 barriers but up to 40 barriers can be served bythis method.

The MTL7798 power feed module would normally be used withstandard barriers such as MTL7787+ and MTL7787P+ because the current/voltage trip protection mechanism of the MTL7798 protectsthe fuses in the barriers.

The MTL7799 dummy barrier can be used instead of the MTL7798for direct ‘feed-through’ connection of a 24V dc supply onto thepower bus. Looping the power feed to each end of the bussed powerallows the removal of individual barriers without loss of power toothers in the chain.

Other units which can use the power bus facility:MTL7706MTL7707+MTL7707P+MTL7741MTL7742MTL7743MTL7744MTL7745MTL7787+MTL7787P+MTL7788+MTL7788R+MTL7789+

HazardousArea

SafeArea

A

!


June 2004

MTL7700 SERIESACCESSORIES

MOUNTING/EARTHING ACCESSORIESMTL7700 Series barriers mount easily and quickly onto standard DINrail which also acts as the intrinsically safe earth.THR2 standard DIN railTHR7000 plated railSpecially nickel-plated T-section (35mm x 7.5mm) DIN rail for use inpotentially corrosive atmospheres. Supplied in 1meter lengths.ISP7000 insulating spacers

Attached to the base of a DIN rail at either end or at intervals(depending upon DIN rail length) to isolate the IS earth from astructural earth.

ERB57S Earth-rail bracket, straightNickel-plated; supplied with two push fasteners, one 14mm earth-railclamp and one 10mm earth clamp for cables ≤16mm2.ETM7 earth terminal

For terminating cable screens and 0V earth returns and securingspare cores to the earth rail. A maximum of two ETM7s per barriercan be accommodated.

TGL7700

ERB57O

TAG57

ERL7ETM7

14mm earth-railclamp

THR2/THR7000

ERB57Sin lower position

ISP7000

ETL7000

10mm earthclamp

IMB57

Snap off extensionwhen using IMB57as a central support

27

7.5

35

14.6

62

50

20

M6 x 16

Ø4.4 M4 x 16

IMB57 Insulating mounting blockOne required at each end of a tagging strip/earth rail. Suitable forlow-profile (7.5mm) and high-profile (15mm) symmetrical DIN rail.

ERB57O Earth-rail bracket, offsetNickel-plated; supplied with two push fasteners, one 14mm earth-rail clamp and one 10mm earth clamp for cables ≤16mm2.

ETL7000 earth terminalProvides connection for routing the IS earth from the DIN rail to anappropriate plant earth. Maximum cable cross-section is 10mm2. Tworecommended per discrete length of DIN rail. See instruction manualINM7700 for more details.

BPL7700 Power Bus linkWhen a number of barriers use a common power supply, the optionalpower link (BPL7700) can be used. Typical applications includehazardous area switches, solenoids and 4–20mA transmitters. Thebarriers it can be used with are the MTL7706, MTL7707+,MTL7787+, MTL7787P+, MTL7789P+ and MTL774X. See next pagefor further details.

82m

m

135m

m

28m

m

66mm 15mm

150mm 10mm

3mm

9mm 14mm

5mm

133.5mm

10mm

3mm

10mm

57mm

14mm

10

43.548 overDIN rail


June 2004

TAGGING ACCESSORIESTwo methods of tagging are available which can be used separatelyor together:1) Individual barrier identification

TH7700 barrier identifiersTH7700 barrier identifiers are supplied clipped on to the tops of individual barriers to provide transparent holders for identification labels.

2) Tagging strip methodTAG57 Tagging strip, 1m lengthCut to size. Supplied with reversible tagging strip label suitable for either MTL5000 or MTL7000 Series module spacing.TGL7700 Tagging strip labels, set of 10 x 0.5mFor use with TAG57 tagging strip. Tags are reversible - one side for MTL7700, the other for MTL700.

HOW TO ORDER

MTL7700 barriersSelect by barrier number and polarity, e.g. MTL7728+

Mounting accessoriesTHR2 Standard DIN-rail, 35 x 7.5mmTHR7000 T-section DIN-rail, specially-plated,

35 x 7.5mm, 1m lengthISP7000 Insulating spacer

Standard earthing/earth-rail accessoriesETL7000 Earth terminal, DIN-rail mountedIMB57 Insulating mounting blockERB57S Earth-rail bracket, straightERB57O Earth-rail bracket, offsetERL7 Earth rail, 1m lengthETM7 Earth terminal, pack of 50

Standard tagging accessoriesTAG57 Tagging strip, 1m lengthTGL7700 Tagging strip labels, set of 10 x

0.5m

Bussed power linksBPL7700 Pack of 100

EnclosuresDX070 Enclosure, for MTL7700 x 5DX170 Enclosure, for MTL7700 x 13DX430 Enclosure, for MTL7700 x 33

Spares (all in packs of 10)SAF7712 Safe-area terminals 1&2HAZ7734 Hazardous area terminals 3&4SAF7756 Safe-area terminals 5&6HAZ7778 Hazardous area terminals 7&8TH7700 Tag holder

LiteratureINM7700 Instruction manual, MTL7700 SeriesINM57ENC Instruction manual, MTL5000/7000

Series EnclosuresCD7700... Customer drawings


June 2004

Region UK UK USA Canada/USA Japan(Authority) (BASEEFA) (BASEEFA) (FM) (CSA) (TIIS)

Systems

Standard EN 50014 EN 50039 3600, 3610 entity CAN/CSA E60079 See CertificatesEN 50020 3611, 3810 UL698, UL913, UL1604

IEC60079, C22.2

Approved for [EEx ia] IIC EEx ia IIC AIS/I,II,III/1/Entity Class 1, Div 2, Gps A,B, Ex (ia) IIC[EEx ia] IIB ‡ EEx ia IIB ‡ ABCDEFG- SCI-942; C,D; Ex nA [iA] IIC T4 Ex (ia) IIB ‡

NI/I/2/ABCD/T4[I/0] AEx[ia]IIC – Class 1, Zone 2, AEx nASCI-942 Entity; IIC T4NI/1/2/IIC/T4 Ta=60ºC except †where Ta=65ºC

Model No. Certificate No.

MTL7706+ BAS01ATEX7217 Ex01E2219 3010737 1345550MTL7707+ BAS01ATEX7217 Ex01E2219 3010737 1345550MTL7707P+ BAS01ATEX7218‡ Ex01E2220‡ 3010737‡ 1345550MTL7710+ BAS01ATEX7217 Ex01E2219 3010737 1345550 C16433MTL7715+ BAS01ATEX7217 Ex01E2219 3010737 1345550 C16434MTL7715P+ BAS01ATEX7217 Ex01E2219 3010737 1345550 C16611MTL7722+ BAS01ATEX7217 Ex01E2219 3010737 1345550 C16435MTL7728+/–/ac BAS01ATEX7217 Ex01E2219 3010737 1345550 C16397MTL7728P+ BAS01ATEX7217 Ex01E2219 3010737 1345550 C16436MTL7729P+ BAS01ATEX7218‡ Ex01E2220‡ 3010737‡ 1345550 C16612‡MTL7741 BAS01ATEX7217 Ex01E2219 3010737 1345550 C16613MTL7742 BAS01ATEX7217 Ex01E2219 3010737 1345550 C16614MTL7743 BAS01ATEX7217 Ex01E2219 3010737 1345550 C16615MTL7744 BAS01ATEX7217 Ex01E2219 3010737 1345550 C16616MTL7745 BAS01ATEX7217 Ex01E2219 3010737 1345550 C16617MTL7755ac BAS01ATEX7217 Ex01E2219 3010737† 1345550 C16450MTL7756ac BAS01ATEX7217 Ex01E2219 3010737† 1345550 C16437MTL7758+/– BAS01ATEX7217 Ex01E2219 3010737 1345550 C16618MTL7760ac BAS01ATEX7217 Ex01E2219 3010737 1345550 C16619MTL7761ac BAS01ATEX7217 Ex01E2219 3010737 1345550 C16438MTL7761Pac BAS01ATEX7217 Ex01E2219 3010737 1345550MTL7764+ BAS01ATEX7217 Ex01E2219 3010737 1345550 C16440MTL7764ac BAS01ATEX7217 Ex01E2219 3010737 1345550 C16441MTL7765ac BAS01ATEX7217 Ex01E2219 3010737 1345550 C16620MTL7766ac BAS01ATEX7217 Ex01E2219 3010737 1345550 C16442MTL7766Pac BAS01ATEX7217 Ex01E2219 3010737 1345550 C16443MTL7767+ BAS01ATEX7217 Ex01E2219 3010737 1345550 C16444MTL7778ac BAS01ATEX7217 Ex01E2219 3010737 1345550 C16621MTL7779+ BAS01ATEX7217 Ex01E2219 3010737 1345550 C16445MTL7787+ BAS01ATEX7217 Ex01E2219 3010737 1345550 C16447MTL7787P+ BAS01ATEX7217 Ex01E2219 3010737 1345550 C16448MTL7788+ BAS01ATEX7217 Ex01E2219 3010737 1345550 C16449MTL7788R+ BAS01ATEX7217 Ex01E2219 3010737 1345550MTL7789+ BAS01ATEX7217 Ex01E2219 3010737 1345550 C16622MTL7796+ BAS01ATEX7217 Ex01E2219 3010737 1345550 C16446MTL7796– BAS01ATEX7217 Ex01E2219 3010737 1345550MTL7798 NI only

Note : For FM compliance, the MTL7700 Series barriers shall be installed in compliance with the enclosure, mounting, spacing and segregation requirements of the ultimate application.

‡ Certified to CENELEC IIB/FM Grps C-G only.

APPROVALS - for the latest certification information visit www.mtl-inst.com/certs_1.nsf


June 2004

ac1/dc Note 3 BASEEFA Group IIC Matched FM (Grps A&B) Matchedref. C L 2 L/R Power C L 2 L/R Power

Model No. (µµF) (mH) (µµH/ΩΩ) (W) (µµF) (mH) (µµH/ΩΩ) (W)MTL7706 + a 0.083 3.05 (4.2) 56 0.65 0.083 4.2 56 0.65MTL7707 + a1/a2/b 0.083 3.05 (4.2) 56 0.65 0.083 4.2 56 0.65MTL7710 + a 3 0.91 74 0.50 3 0.91 74 0.50MTL7715 + a 0.58 1.45 66 0.56 0.58 1.45 66 0.56MTL7715P + a 0.580 0.33 28 1.09 0.580 0.33 28 1.09MTL7722 + a 0.165 1.45 45 0.81 0.165 1.45 45 0.81MTL7728 +/-/ac a 0.083 3.05 (4.2) 56 0.65 0.083 3.05 (4.2) 56 0.65MTL7728P + a 0.083 1.82 (2.51) 44 0.83 0.083 1.82 (2.51) 44 0.83MTL774X b3 2.86 96 742 — 2.86 96 742 0.039MTL7755 ac a1/a2 100 0.46 145 0.225 100 0.46 145 0.225

b 100 0.13 69 0.45 40 0.13 69 0.45c 40 0.41 73 0.45 40 0.13 69 0.45

MTL7756 ac a1/a2/a3 100 0.46 145 0.225 100 0.46 145 0.225b1 100 0.13 69 0.45 40 0.13 69 0.45b2 100 0.06 44 0.675 40 0.13 69 0.45c1 40 0.41 73 0.45 40 0.13 69 0.45c2 40 0.23 61 0.60 40 0.06 44 0.675

MTL7758 +/- a1/a2 11.1 0.07 26 1.40 11.1 0.07 26 1.4b 11.1 0.02 10 2.8 8.8 0.02 10 2.8

MTL7760 ac a1/a2 3 0.91 74 0.5 3 0.91 74 0.5b 3 0.20 27 1.00 3 0.20 35.6 1.00

MTL7761 ac a1/a2 4.9 3.72 163 0.225 4.9 3.72 163 0.225b 4.9 0.91 62 0.45 0.31 0.91 62 0.45c 0.31 3.72 81 0.45 0.31 0.91 62 0.45

MTL7761P ac a1/a2 4.9 56 613 0.058 4.9 56 613 0.058b 4.9 14 236 0.115 0.31 14.0 236 0.115c 0.31 56 306 0.115 0.31 14.0 236 0.115

MTL7764 + a1/a2 1.41 240 1000 0.036 1.41 240 1000 0.036b 1.41 61 360 0.072 1.0 61 360 0.072

MTL7764 ac a1/a2 1.41 240 1000 0.036 1.41 240 1000 0.036b 1.41 61 360 0.072 0.125 61 360 0.072c 0.125 240 500 0.072 0.125 61 360 0.072

MTL7765 ac a1/a2 0.580 1.45 66 0.56 0.580 1.45 66 0.56b 0.580 0.32 22 1.125 0.58 0.32 31.6 1.12

MTL7766 ac a1/a2 1.41 5.8 151 0.24 1.41 5.8 151 0.24b 1.41 1.47 58 0.48 0.125 1.47 58 0.48c 0.125 5.8 75 0.48 0.125 1.47 58 0.48

MTL7766P ac a1 1.41 1.47 78 0.471 1.41 1.47 78 0.471b 1.41 0.34 29 0.942 0.125 0.34 29 0.942c 0.125 1.15 39 0.942 0.125 0.34 29 0.942

MTL7767 + a1/a2 0.58 1.45 66 0.56 0.58 1.45 66 0.56b 0.58 0.32 22 1.125 0.58 0.32 22 1.125

MTL7778 ac a1/a2 0.083 16 107 0.33 0.083 16 107 0.33b 0.083 3.05 (4.2) 42 0.33 0.083 4.0 107 0.654

MTL7779 + a1/a2 0.083 3.05 (4.2) 56 0.65 0.083 3.05 (4.2) 56 0.65b NOT PERMITTED

MTL7787 +/- a1 0.083 3.05 (4.2) 56 0.65 0.083 3.05 (4.2) 56 0.65a2 0.083 — — — 0.083 — — —b 0.083 3.05 (4.2) 56 0.65 0.011 4.2 56 0.65

MTL7787P + a1 0.083 1.82 (2.51) 44 0.835 0.083 1.82 (2.51) 44 0.83a2 0.083 — — — 0.083 — — —b 0.083 1.82 (2.51) 44 0.835 0.78 2.51 44 0.835

MTL7788 + a1 0.083 3.05 (4.2) 56 0.65 0.083 3.05 (4.2) 56 0.65a2 3.0 0.91 74 0.5 3.0 0.91 74 0.5b 0.083 0.33 25 0.92 0.083 0.33 25 0.92

MTL7788R + a1 0.083 3.05 (4.2) 56 0.65 0.083 3.05 (4.2) 56 0.65a2 3.0 0.91 74 0.5 3.0 0.91 74 0.5b 0.083 0.33 25 0.92 0.083 0.33 25 0.92

MTL7789 + C 0.083 16 106 0.33 0.083 16 106 0.33MTL7796 +/- a1 0.1 4.91 64 0.56 0.1 4.91 64 0.56

a2 0.22 13 136 0.26 0.22 13 136 0.26b 0.1 1.94 34 0.81 0.096 1.94 34 0.81

Notes: 1 ac indicates a non-polarised star connected barrier configuration.2 When the external circuit contains no lumped inductance greater than 10mH, the cable inductance may be increased to the values within

parenthesis.

For further barrier channel configuration data, please refer to the relevant certificate.

MAXIMUM CABLE PARAMETERS

Model No. ac1/dc Note 3 BASEEFA GroupIIB Matched FM (Grps C-G) MatchedRef. C L L/R Power C L L/R Power

(µµF) (mH) (µµH/ΩΩ) (W) (µµF) (mH) (µµH/ΩΩ) (W)MTL7707P + a1 0.65 5.34 125 2.64 0.65 5.34 125 2.64

b 0.65 5.34 125 2.64 0.587 5.34 125 2.64MTL7729P + a1 0.65 5.65 127 2.64 0.65 5.65 127 1.19


June 2004

Module No. Bussed MTL7000 MTL7000 MTL7000 MTL700 MTL700 MTL700 TypicalPower Equivalent Original ATEX equivalent Original ATEX Application

Certificate Certificate Certificate Certificate Number(s) Number(s) Number(s) Number(s)

MTL7710+ No Half of Ex95C2261 BAS99ATEX7285 MTL710+ Ex832452 BAS01ATEX7202 4/6VMTL7162+ Systems

MTL7715+ No N/A N/A N/A MTL715+ Ex832452 BAS01ATEX7202 12V SystemsMTL7715P+ No N/A N/A N/A MTL715P+ Ex92C2373 BAS01ATEX7202 12V SystemsMTL7722+ No MTL7122+ Ex95C2261 BAS99ATEX7285 MTL722+ Ex832452 BAS01ATEX7202 General PurposeMTL7728+/- No MTL7028+/- Ex95C2261 BAS99ATEX7285 MTL728+/- Ex832452 BAS01ATEX7202 Analogue / Digital

MTL7128+/-MTL7728ac No N/A N/A N/A MTL728ac Ex832452 BAS01ATEX7202 General PurposeMTL7728P+ No MTL7128P+ Ex95C2261 BAS99ATEX7285 MTL728P+ Ex92C2373 BAS01ATEX7202 Analogue / DigitalMTL7755ac No MTL7055ac Ex95C2261 BAS99ATEX7285 MTL755ac Ex832452 BAS01ATEX7202 RTD, GroundedMTL7756ac No MTL7056ac Ex95C2261 BAS99ATEX7285 N/A N/A N/A RTD, GroundedMTL7758+/- No N/A N/A N/A MTL758 Ex83453 BAS01ATEX7217 Active sensors,

ThermocouplesMTL7760ac No N/A N/A N/A MTL760ac Ex832452 BAS01ATEX7202 Active sensors,

ThermocouplesMTL7761ac No MTL7261ac Ex95C2261 BAS99ATEX7285 MTL761ac Ex832452 BAS01ATEX7202 Strain GaugesMTL7761Pac No MTL7061Pac Ex95C2261 BAS99ATEX7285 MTL761Pac Ex92C2373 BAS01ATEX7202 Load cell

MTL7161PacMTL7764+ No MTL7164+ Ex95C2261 BAS99ATEX7285 MTL764+ Ex832452 BAS01ATEX7202 High resistanceMTL7764ac No MTL7264ac Ex95C2261 BAS99ATEX7285 MTL764ac Ex832452 BAS01ATEX7202 Strain / Level

GaugesMTL7765ac No N/A N/A N/A MTL765ac Ex832452 BAS01ATEX7202 General PurposeMTL7766ac No N/A N/A N/A MTL766ac Ex832452 BAS01ATEX7202 Strain GaugesMTL7766Pac No MTL7066Pac Ex95C2261 BAS99ATEX7285 MTL766Pac Ex92C2373 BAS01ATEX7202 Strain Gauges

MTL7166PacMTL7767+ No MTL7167+ Ex95C2261 BAS99ATEX7285 MTL767+ Ex832452 BAS01ATEX7202 Dual MTL715MTL7779+ No N/A N/A N/A MTL779+ Ex832452 BAS01ATEX7202 Dual MTL728MTL7787+/- Yes MTL7087+ Ex95C2261 BAS99ATEX7285 MTL787S+ Ex832452 BAS01ATEX7202 Analogue / Digital

MTL7187+MTL7787P+ Yes MTL7087P+ Ex95C2261 BAS99ATEX7285 MTL787SP+ Ex92C2373 BAS01ATEX7202 Analogue / Digital

MTL7187P+MTL7788+ Yes N/A N/A N/A MTL788+ Ex832452 BAS01ATEX7202 TransmittersMTL7788R+ Yes N/A N/A N/A MTL788R+ Ex832452 BAS01ATEX7202 1—5V systemsMTL7796+/- No MTL7096- Ex95C2261 BAS99ATEX7285 MTL796+/- Ex832452 BAS01ATEX7202 Vibration sensors

MTL7196-

CORRELATION BETWEEN MTL7700 — MTL7000 — MTL700 BARRIERS (IIC)

Note 3 : The circuit configuration for the output parameters givenin the table ‘Maximum Cable Parameters’ are as follows:-

a - Single channel barrier.a1 - First channel of a dual/triple channel barrier.a2 - Second channel of a dual/triple channel barrier.a3 - Third channel of a dual/triple channel barrier.b - Both channels of a dual channel barrier connected in

parallel, with respect to earth.b1 - Two channels of a triple channel barrier connected in

parallel, with respect to earth.b2 - Three channels of a triple channel barrier connected in

parallel, with respect to earth.b3 - Both channels of each switch input connected togetherc - Both channels of a dual channel barrier interconnected,

with no earth return.c1 - Two channels of a triple channel barrier interconnected,

with no earth return.c2 - Three channels of a triple channel barrier interconnected,

with no earth return. This assumes two of the channels arein parallel.

shunt diode safety barriers mtl 7700 series data sheet diode safety barriers mtl 7700 series ... ♦...

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